NB: this question has had some extensive editing. I apologize to those who replied early based on unclear premise.

TL; DR two societies (druids & nomads) each discovered one kind of mana (resp. blue & orange) and never suspected the existence of the other kind (resp. orange & blue), even though both kinds are interacting with their environment. I am looking for the simplest explanation for that.

Premise

In my story, magic operates through a mana field. Mana comes in two varieties: blue and orange. Flows of mana of either kind are subject to elemental influences: mana streams are naturally found along water or wind streams, trapped into some geological sediments and expelled with lava flows. All over the world, evolution has driven a few animals and plants to take advantage of both kind of mana.

Humans however, like most living species, are not normally able to perceive the presence of mana.
Some druidic society, living in forest areas, has discovered a special berry. When consumed it temporarily modifies the vision, allowing to see flows of blue mana. The way this works is by making blue cones sensitive to blue mana rather than normal blue light, hence dense concentrations of mana appear blue to those who consumed the berry.
They have prospered thank to the use of magic, but never discovered the existence of orange mana, even far into medieval times, long after the existence and usage of magic has been well established, studied and theorized.

On the contrary, a society of nomads living in an arid desert has discovered independently the use of orange mana, by consuming the venom of some snake. The effect on vision is similar but affects orange cones, which among humans only some women possess. The venom also affects green cones but to a lesser extent. Therefore this society has mostly female mages and has grown to be matriarchal as a result. For the purpose of the question, let's say that around 30% of women are born with this additional cone.

At some point, descendants of these nomads became sedentary and established cities in the desert. They also theorized magic and have a good grasp of it, though not aware of the advances of the druidic societies.

For my story, it is very important that at some point in history, a cultural clash between these two civilizations be rooted in their completely different handling of magic.

Question

Given that

Both societies knew early on about magic ;

Both societies had long-lasting scientific tradition of describing the fauna and flora around them ;

Both kind of mana are pervasive to the world and necessary for a complete understanding of the species that use them;

I expect that if one waits long enough, both societies are bound to find out about both kind of manas. After centuries, they still did not.

What is the simplest possible explanation (i.e. as little new elements as possible) that prevented or delayed these discoveries until late medieval times?

Some limitations I'd like to emphasize:

Both kind of mana are (roughly) equally available in both regions.

Apart from druids and nomads, other societies have discovered magic too, but never both types.

Although both the berry and the snake are endemic of the said forest and desert, respectively, they are just two examples of species that found a use in becoming sensitive to mana. There are many non-endemic species that use either kind of mana as part of their metabolism.

Your answer may or may not involve the existence of other ways to become sensitive to mana.

The nomads and druids descendants have lived separately before the above-mentioned clash. They know of each others through tales of itinerant merchants, but they never suspected that their magics were so deeply different.

More Background Info

The following is not necessary to answer the question, but provides background for the curious.

Mana in itself is actually colorless, the names only refer to their effect on human vision.

In my world, the discovery of the berry is the root of druidism, as druids maintained their privileges in early human groups by consuming the berry and using mana to become valuable members of the group, including communicating with other beasts that consume the berry.

The reason the berry has this effect is a dissemination strategy: the berry traps mana so that crows, who consume the berry in their normal diet, can spot the berry easily and spread seeds throughout the forest.

The reason the snake's venom has this effect is part of their mating behavior: males harbour beautiful patterns obtained by fixing orange mana to their scales. The pattern only reveals to females that they have bitten as part of the courtship ritual, but not to potential predators, insensitive to orange mana.

both societies have been in contact with dragons, which are among the rare creatures naturally sensitive to both kinds of mana. They are far more intelligent than humans but do not normally bother with learning how to communicate with their delicious preys.

Final edit: why did I chose this answer?

Since there were several very good answers I guess I should clarify this. In my view Cort Ammon's answer involves the smallest set of additional ingredients: it does not involve either society to be particularly narrow minded, but simply ideological reinforcement traps, which are certainly a real thing. In the same category, IT Alex's and Ister's answers were strong contenders.

I really liked the ripple/repelling/void magic sort of ideas, but they set big constraints on the future developments of how magic works in my world.
Answers based on interaction between the venom and the berry or other biological stuff were also great, but I maintain that they fail to explain why druids (resp. nomads) were not worried about other species.

$\begingroup$Also, if you do add to your question that the berry and snake are not the only sources of mana sight, that there are other orange sources near the druids and blue ones near the nomads, then essentially you are asking "If this was sitting next to them all along, why didn't they know it?" Your question ceases to be something that can be reasonably answered, and suddenly anyone can throw out whatever answer they want... eg: 1) it is 95% subjective 2) it's one of those "You should tell us why they haven't figured it out." things, as it is essentially creating part of your story.$\endgroup$
– LoduwijkNov 8 '18 at 21:19

1

$\begingroup$I'm thinking more about your more recent comments that perhaps we're missing something and it's not clear. How about this? When you write things like "neither the snake nor the berry are necessary conditions for the discovery," are you trying to imply there that there are other similar ways to make the discovery by other objects in the area with similar effects? If yes, you never actually explicitly state that, and I certainly do not assume it by anything in the question (and my silly answer would still stand). If not, I'm not sure what you imply by that (how else would they discover?)$\endgroup$
– LoduwijkNov 8 '18 at 21:38

12 Answers
12

Simple. Berries are particles. Snake venom is a fluid, so it has wave like behaviors. I swear to god, holy wars have been raise in the science class room whether light is a particle or a wave, despite the best efforts of the teacher to teach that they're two sides of the same coin. Why should your manna be any different?

It's fascinatingly difficult to change your mind about something like the nature of light. Once you pick up your own preferred way of viewing light, you tend to craft your experiments in ways which reward that way of thinking. Magic could easily be structured the same way. Once you start down a path, it becomes harder and harder to see from the other viewpoint.

$\begingroup$I think the particle/wave analogy a bit far-fetched, but the idea that both mana are of nature so different that orange mana is not conceivable in the druidic scientific system and vice versa is quite nice!$\endgroup$
– AlexisNov 8 '18 at 19:49

1

$\begingroup$@Alexis I draw the analogy because it has the same duality. Light isn't a particle and it isn't a wave. It's how we look at it. Its how we chose to simplify it.$\endgroup$
– Cort AmmonNov 8 '18 at 19:51

8

$\begingroup$And if you start to think that light is a particle. How you treat light and how you experiment on light will lend itself to cementing your belief that it is a particle. Same goes for waves. It's only when you put it in really absurd situations, like the single-photon double slit that you realize that neither belief was right.$\endgroup$
– Cort AmmonNov 8 '18 at 19:54

$\begingroup$Ok but historically, light has been alternatively considered as wave or particle, with good arguments on both sides. How come the druids never considered that mana could be wave like and the nomads never considered it could be particle like, which would have led to experiments demonstrating the existence of the other type of mana?$\endgroup$
– AlexisNov 8 '18 at 19:57

1

$\begingroup$They didn't need to, and they had the tiniest of inclination to not want to. For example, the tiniest bit of religious influence would be more than sufficient to convince you one way or the other, as long as your practical experimentations don't yield conflicting results (silence the heretic!)$\endgroup$
– Cort AmmonNov 8 '18 at 20:00

It's simple. The snake that induces the ability to see the orange mana only exists in the land of the nomads. The berries that induces the ability to see blue mana only exists in the land of the civilization.

Though, eventually, there will be wanderers that go into these lands and discover the oranga mana inducing snake or the blue mana inducing berry. But, the nomads had built up through many generations a tolerance to the snake venom. So, if a wanderer is to consume the venom, she might be able to see orange mana, but only for a little while before collapsing and dying. Same thing with the berries, they're poisonous, and the blue mana users have through generations become tolerant to it, but the nomads haven't.

Also, just to take note of; venom only affects people when injected into the blood. Nothing will happen if you drink venom. Though poison on the other hand, affects one both through blood injection and consumption. Just have that in mind when writing on.

$\begingroup$Yeah, it's quite interesting actually. Very few snakes are poisonous, almost all are venomous. Frogs on the other hand, are more often poisonous, sometimes dispersing this poison through the skin on their back, meaning that only a mere touch can poison you.$\endgroup$
– A. KvåleNov 8 '18 at 21:08

2

$\begingroup$I did +1, but would like to note that the simple version of "eating venom does not harm you" can be dangerous. It does not harm you if it does not come into contact with anything else in you and passes straight through. But if you have any problems on the inside, such as a sore on your stomach (which you might not even know about), then the venom can cross over and harm you.$\endgroup$
– LoduwijkNov 8 '18 at 21:14

2

$\begingroup$@Aaron You make a point. Any internal sore, either in the stomach, throat or the mouth can allow the venom to enter the blood stream.$\endgroup$
– A. KvåleNov 8 '18 at 21:31

2

$\begingroup$@WhatRoughBeast it is possible that in both cases the venom/poison were initially not as strong, (and did not produce as strong a sensitizing effect.) After discovery the Druids and Nomads each selectively bread the the plants and snakes to produce stronger sensitizing effect, which had the side effect of increasing the toxic side effects.$\endgroup$
– Mr.MindorNov 9 '18 at 20:14

I have heard it claimed that because China learned to make really good teacups really early, they never needed to make drinking glasses; and therefore from the 14th to the 19th century they missed out on all the inventions derived from glass technology including windows, microscopes, telescopes, glasses, chemistry flasks and test tubes, mirrors and so on.

In other words, Thing A works so well you don't invent Thing B, so you never discover that Thing B has a bunch of benefits.

Of course, I've also seen it noted that China did, in fact, have glass. But we don't have to let the facts of our world influence your world!

You could have your different societies follow a similar path: The society that discovered the secrets of Orange Mana was vaguely aware of Blue Mana but regarded it as a mere curiosity you can't do anything with, why waste time studying it given the obvious strength of Orange Mana? The other society got strong at Blue Mana first, and ignores Orange Mana for the same reason.

Alternately, you could have a compatibility problem - much like it's arbitrary whether a country drives on the Left or on the Right, but once the convention is established it's costly and irrational to go against it.

You could say that consuming Orange Mana creates waves in the Blue Mana fabric making it behave unpredictably, and vice-versa. Explain is as power rushing in to equalise nature's forces, or a ship going east to west sending waves north and south.

Thus, if Orange Mana got established first in your city, anyone who tried to use Blue Mana would get unpredictable, wild-mage-style results that would either scare them off or kill them.

That could also lead into the societies getting off on a bad footing. You might also want some sort of combat mechanic where people who are well trained try to cause these ripples intentionally.

$\begingroup$This is interesting because even before talking about usage, comprehension of orange mana would be very difficult to anyone using blue mana. I can imagine a compromise where both civilizations believe that magic just so happens to be sometimes unstable. It would also explain a feature I desired which is that only very specific creatures (like dragons) use both.$\endgroup$
– AlexisNov 9 '18 at 0:28

2

$\begingroup$+1 for historic example; +1 for the idea that using one makes the other unstable (rippling). I would take it one step further, though, if Orange-using plants/animals are established in the desert, then their very presence (in number) would inhibit the development of Blue-using species. In the end, this would lead to distinct ecosystems even before humans come into play, and therefore the nomads, surrounding by an exclusively Orange-using ecosystem, would not even be aware that a Blue-ecosystem exists. Even better... it may be that a Green or Violet ecosystems exist elsewhere.$\endgroup$
– Matthieu M.Nov 9 '18 at 11:32

Your "Blue cones" in the eye are sensitive to ultraviolet light, "orange cones" are sensitive to infrared. They are are both just outside the spectrum of frequencies visible to human eye, but on opposite ends of the spectrum. So the ability to see one of them has nothing to do with ability seeing the other.

In fact, you can make it so that the ability to see ultraviolet could come at the cost of the ability to see some deeper reds that are visible to normal humans. And vice versa, seeing infrared costs you the ability to see blue. Finally, you could make it that taking both blue berry and snake venom will pull visual range in opposite directions, leaving a person blind.

Also: some birds can see ultraviolet; some snakes can see infrared.

Edit: Biology.SE tells us that humans have some biologic mechanisms that could let them see either ultraviolet or infrared, but they are different mechanisms.
So your blue berries weaken or destroy the eye lens (creating aphakia), or make it transparent to UV rays. The venom mutates eye proteins and shifts the range that "red" eye cone can detect.

Edit 2: If you want somebody to do both kinds of magic, you can assume that ability to see UV and IR can happen in the same person, i.e. the two different mechanisms do not affect each other (my statement above against this is a hypothesis, not a fact).

$\begingroup$Can you elaborate? How does that explain why each society discovers only one type?$\endgroup$
– AlexisNov 8 '18 at 19:33

$\begingroup$I like your answer because I find it simple and elegant that one ability hinders the access to the other, but that prevents the existence in the future of mages that can manipulate both kind of manas. I'd rather avoid that if possible (it violates the 1st bullet point, which I reformulated to make it clearer).$\endgroup$
– AlexisNov 8 '18 at 19:46

$\begingroup$@Alexis "Can you elaborate? How does that explain why each society discovers only one type?" Obviously because there are no desert snakes in the forest, nor forest berries in the desert.$\endgroup$
– RonJohnNov 9 '18 at 9:28

$\begingroup$@RonJohn My comment was posted when the answer was literally just the 1st sentence of the answer that is now displayed. After the later edits, I added another comment. Can you please not assume by default that I am stupid?$\endgroup$
– AlexisNov 9 '18 at 9:32

$\begingroup$@Alexis "Although both the berry and the snake are endemic of the said forest and desert ... they are just two examples of species that (are) sensitive to mana. There are many non-endemic species that use either kind of mana as part of their metabolism." Your question in no way makes clear whether these societies know that other species use mana, nor the technological level of the societies, nor how much research it takes to discover that species use mana, too. For example, how many centuries have we been studying the human body? And yet still we discover new organs.$\endgroup$
– RonJohnNov 9 '18 at 9:41

I'm going to go another way. They are aware of the magical effects, but only tangentially as a theoretical manner, and find that it is completely impractical and useless. Due to the difficulty of learning about the other "kind" of magic, they both have an incorrect model of what the other magic is.

So Druids have limited ability to manipulate Orange mana. But the Orange mana they have learned to manipulate is only when there is a saturating Blue mana field, so it is highly inefficient.

Imagine if the only way you could see a tree was to arrange for a pile of herdbeasts to stampede through an area, and watch where they avoided the tree. From that you could ride a herdbeast and harvest the fruit of the tree.

It would be better to call the Druid's use of Orange magic as Blue-void magic, and the Nomad's use of Blue magic as Orange-void magic. This "void magic" is incredibly expensive to study or use, and produces next to no useful results for both parties, so is considered a dead end research-wise.

Both are aware that Dragons can naturally harness void magic.

Rarely, people engage in huge research projects where they produce huge mana flows and induce voids in order to capture and manipulate void magic, and get inconsistent and maddening results.

A mechanism for generating the torrents of magic required to manipulate the "void" magic could involve necromancy or human sacrifice; you first charge a human full of normal magic, then kill them to release it all at once (or produce a controlled flow through unpleasant means). That would make "void" magic dispicable and shunned.

$\begingroup$In this scenario (where they know about both), they could just as easily be motivated by the distrust of the other group: that is, blue mana users despise orange mana users, and believe them to be degenerate in some way.$\endgroup$
– jpaughNov 9 '18 at 16:21

The chemicals that allow you to see each type of Mana cancel each other out - too much of either is poisonous, but administering the other chemical acts as an antidote.

Because the symptoms of an overdose are clearly visible, and hard to fake (brightly glowing Blue/Orange eyes?) no one in either society has ever been "stupid" enough to take the Antidote without being poisoned in the first place.

Even if they did - any traces of having taken the other chemical within the past 3 months would reduce/cancel out the effects unless you upped the dosage, at which point other toxins present in the Berries and Snake venom would cause your death instead.

The ability to "swap" back and forth would require either a prolonged abstinence to "flush" your system, or a refined/isolated sample of the chemical extracted from the berries and venom.

On the other hand, everyone in the nomadic society has a form of blue-yellow color blindness. What you can't see can not possibly be real, right?

It's only when a member of the mage society breeds with a member of the nomadic society, do you have a chance of an offspring without any color blindness. Thus, some children of powerful nomadic witches and druidic mages (in the future) can have both powers.

$\begingroup$You know I love that idea because that would actually be really interesting for the "reconciliation" part that my store features afterwards. I am concerned about the realism that two large groups would both be systematically color blind.$\endgroup$
– AlexisNov 9 '18 at 9:24

1

$\begingroup$@Alexis If the tribe was founded by only a few members, and those founders had color-blindness, it is not inconceivable to have an entire population with color-blindness. If you look at Wikipedia, 10% of Arabs have color-blindness, compared to only 0.8% of Fijians, and these are extremely large populations. Moreover, I suspect that if a significantly large population has red-green color-blindness, even those with normal vision may not know what "red" is (it's never taught them), so it can take a while before someone says "aha! this is what the witches see"$\endgroup$
– DharaNov 9 '18 at 9:31

Simple. In order to learn how to use something you need to see it to study it.

The Druids have only ever seen blue mana and been able to manipulate it while under the effects of the berry. This has allowed them to craft spells around using blue and its limitations.

The nomads likewise have only ever seen orange due to the lack of the berry and have only learned the properties of orange mana.

Skilled practitioners could likely have learned to use magic by feel after using it so frequently with the berry/venom much in the same way as you can navigate your house in the dark. It is something that anyone could do with study but it is night impossible without the "training wheels" of the "sight".

$\begingroup$I believe I see your point but it remains that the forest (resp. the desert) is inhabited by other species whose metabolism is based on orange (resp blue) mana. Why did the druids (resp. nomads) never studied these creatures enough to discover that there was a discrepancy between their understanding and the facts?$\endgroup$
– AlexisNov 8 '18 at 20:57

$\begingroup$@Alexis "it remains that the forest (resp. the desert) is inhabited by other species whose metabolism is based on orange (resp blue) mana." You say that these people have observed nature. But have they really studied it with microscopes and x-ray crystallography and all the other equipment we've invented (or perfected) in the past 150 years? Somehow, I'm skeptical of that.$\endgroup$
– RonJohnNov 9 '18 at 9:33

$\begingroup$@RonJohn neither societies had discovered microscope nor x-ray crystallography at that point in history.$\endgroup$
– AlexisNov 9 '18 at 9:58

1

$\begingroup$@Alexis then it's perfectly reasonable that -- even though there are forest species that rely on orange mana -- the druids don't have the technology or scientific knowledge base to discover orange mana. Ditto for blue mana and the not-nomads.$\endgroup$
– RonJohnNov 9 '18 at 10:14

1

$\begingroup$@Alexis We humans are stupid folk and incorrectly attributed many ailments to having too much blood in the dark ages. Misinterpreting the reasons for things is kind of our calling card at this point.$\endgroup$
– IT AlexNov 9 '18 at 13:25

There are few factors working in common. Hopefully my answer will work on a broad basis not only the Druids vs Nomads situation:

Various mana manifestation

Mana in itself is actually colorless, the names only refer to their effect on human vision.

As you've mentioned you use the mana "colours" as a reference of how Druids and Nomads perceive it. They see it and can recognise it thanks to that. But actually depending on the triggering agent the mana can manifest through various senses. For example in the area where Druids live there is a specific kind of grain that produces "orange" mana sensitiveness through a sense of touch. If Mice and other rodents eat it they become orange mana sensitive through a specific whiskers movement. Similarly predators eating rodents can feel the orange mana - feline predators through whiskers (they even "purr out" the mana!), birds through feather movements etc. On the other hand in the area where Nomads live there are some flowers with blue petals that - if touched - make you smell the blue mana as a kind of specific sweetish scent. This is used by bees and other insects to discover and use it.

You can play with it even more. Mana might manifest as a range of lights depending of the trigger, so orange mana actually can span to infrared while blue mana sometimes is perceived through ultraviolet (both colours are outside human vision range so goes unnoticed even if someone stumbles upon it). It can be that mana can also manifest as a sound - orange as low tones to infra-sounds (that's why cat purrs when emitting orange mana!) blue as high tones to ultra-sounds (did you notice this little tingling sound when you smell dandelions?). Some mana are available to only those animals that have specialised organs to detect it and are totally inaccessible for humans.

Druids sometimes add the aforementioned grain to their food and they can feel that little tangling of skin. But is it really there? The best guess they've reached so far is that the only mana known to them is manifesting in a different form but for some reasons they didn't manage to catch that link yet. Many yet just assume that the funny feeling is a kind of allergy-like reaction to food.

Uneven spread of mana manifestation

Both kind of mana are (roughly) equally available in both regions.

Apart from druids and nomads, other societies have discovered magic
too, but never both types. Although both the berry and the snake are
endemic of the said forest and desert, respectively, they are just two
examples of species that found a use in becoming sensitive to mana.

There are many non-endemic species that use either kind of mana as
part of their metabolism.

Due to the feedback that lead to a different evolutionary paths the way specific kind of mana is perceived in specific location depends on the location itself. Other natural influence might impact it (like different magnetic field, air pressure etc.). In general in Druids' region blue mana can be seen and heard but orange can be smelled and touched. It's opposite though in the Nomads region (or you can mix things in whatever way you wish to).

Animals mostly need just one kind of mana (or to be specific - depend on one) so they specialise in recognising one or another ignoring the rest. As dragons are powerful magical creatures they need and use both - after all their excellent senses of smell and hearing let them notice and locate sources of both kinds wherever they are (they are also among most mobile animals so from evolution point of view they simply had to adapt that way) .

Humans are magical enough to use both kind of mana but one mana kind is enough for them. As a result their senses with mostly vision and rather strong but not that good hearing allow them to easily recognise the visual mana manifestation (unless outside of their vision range). The other ways of mana manifestation is not strong enough to be useful (eventually in areas where light-base mana manifestation is invisible other kind, mostly sound based can step into giving you another range of possibilities). This way each society discovered only the one kind of mana that for humans is strongest in their area, being ignorant to weak traces of the other mana manifestation.

Lack of training

While nature work by instincts you need to learn how to use mana. Different mana kinds require different skills to use it for magic. Druids are aware of the blue mana so they found ways to use it. They train that skills. This adds another layer of ignorance about the orange mana (I can't use it for magic so it still can be that allergic reaction rather than mana)

Selective/simplifying explanation

Since humans know about mana they can even notice there are various representations of it. Sometimes they can even link that if by touching a dandelion they can hear mana, they can also use berries to see it. So they expect to all mana be the same. You can smell something or feel the tingling sensation? Well, it might be mana as well, but the traces are too weak to use "standard" method. Maybe it's underground source, so you still can't see it and you're unsure where to dig to find it.

This way they remain oblivious to the other kind of mana that is not a basic kind for them. Unless they clash with the other mana-ers they will remain in that state.

Further impact

Note that this approach opens a wider area for future plots.

In future people might be seeking the green mana that according to scientific theory build upon Druids and Nomads meeting (after unrest has finally settled) is supposed to be the strongest one as it is supposedly combination of both orange and blue one. This search though eventually yields a vain effort as there is no such thing as green mana (or maybe it is but...)

Some time after Druids meet Nomads they met another society that claims usage of whistling mana. This sets another round of speculations about nature of mana (as we, omniwise know this is simply another way blue mana manifests as a high pitch sound)

societies where light mana is invisible to humans will relay on people with better senses other that vision - for example blinds might be the most powerful mages. It can lead to various social and cultural repercussions (blind your child young to make it more powerful mage in future?)

$\begingroup$+1 Societies can deviate so far based simply on a lack of need. This is one of the reasons that the east lagged so behind in some areas of science and inventions. They never found a reason to create glass (thanks to the creation of china and use of paper windows/screens) and as a result never delved into exploring optics, developing telescopes and microscopes.$\endgroup$
– CybersparkNov 12 '18 at 10:55

Its entirely believable that these societies reached well into their medieval ages without being widely aware of the existence of the other mana. You don't even need to invoke necessity, some great imbalance, special knowledge, or anything. You just need a little creative geography like a huge ocean and two separate continents, or a large desert filled with death by dragon - mixed with humans being human.

When these societies started they were quite likely small, probably village sized, a large one would have had a thousand people. The discovery/knowledge of the berry/venom would have lead to conflicts. Villages would have banded together to reign in a particularly successful village, killing their magic users, or being wiped out in the effort. Perhaps some magic users toured the lands as warlords, only for everything to fall apart when the next in line was magically inept. Eventually a few groups would have started to consolidate into city-states or kingdoms. The most successful method for winning those wars would have been a mix of warriors (and their weapon tech), and the mages. They would have become the main players in their respective societies.

Warriors for all they are good at extracting taxes, are not great proponents for study, or liberty - unless it helps them win. They would have opposed institutions of free thinking, and learning. After all students don't make stuff the warriors can take. And its easier to keep people in line when you control their thinking.

The Mages (be they Druid/Nomad) would have had the main political power, but would not want this power democratised. After all training a new mage would be risky. There is only so much wealth up there, the more people with a right (or ability to fight for it) the less wealth to go around and the more unstable society becomes. Also a weak mage would fear new mages, because they could easily be killed and usurped. A strong mage would be less fearful of training a new mage but would baulk at training too many mages, as they could be taken out be shear numbers.

Slowly these city states would merge through conquest, imperialism, trade, etc.. to form unions or countries. But that is a slow process taking generations. Each change of leadership (particularly if instigated by war) would cause the political elite to further strengthen their power. This would have manifested in slaughter, book/scroll burning, religious hegemony, propaganda, and even highly selective state based training (aka brainwashing schools). Different ideas, ways of life, techniques would have been eliminated to ensure power remained in the hands of the elite.

Unless the elite had a use for it. The scientific revolution occurred because a number of educated elite, and literate middle class individuals were sanctioned to discover things (with a budget) by various kings and queens. They did not sanction it because they liked science, or thought it amusing, or desired a legacy. They sanctioned it because there was an arms race, both economical and militarily going on, and not having science was too risky.

The last piece of the puzzle is continuity, the knowledge needed to be distributed and preserved, even when the original power that discovered it failed. Many things in the scientific revolution were invented by France (and french men). If all of there knowledge was destroyed in the world wars by the invading imperial force, and no one else had a copy of it. Centuries of study would have been lost. But fortunately the knowledge was copied, distributed and improved on by others.

Case in point:

Electricity was known as far back as the Greek Philosophers using amber rods to generate static electricity. It was well studied, some even used associated processes to electro-plate jewels. Many earlier civilisations quite likely were aware of this phenomena even though we have lost any accounts they had of it. Yet it took on the order of (at least) 2000 years to develop the first widely useful electrical device - A light-bulb (1802), and a scale-able means to produce electricity - the battery (1800), and the eletric-dynamo (1831). To actually enable wide-spread use. the scientific revolution started about 1543, that is even after establishing the circumstances needed for a healthy scientific community, it still took roughly 287 years to figure out how to use electricity for everyone (and we are still figuring out how to deploy that knowledge).

So why is it that the respective civilisations figured out about blue/orange mana? They had an enabler, the berry/venom that a very low tech people could exploit, which ensured the continuity required to gather the knowledge of its use. And in that exploitation caused other avenues of endevour to be cut off. Not because of necessity, just because of politics, and the very human desire to have the good life.

The realisation that there is another mana out there could have come about by happenstance, independently for each peoples without a cross-cultural exchange fueled by a strong general scientific continuity - or by the technology finally maturing enough for there to be significant long-term cultural exchanges.

Why do they have to be two distinct Manas? Perhaps there is only 1 Mana, which is colourless as you say, and it depends purely on the berries/snake venom/whatever other local produce is consumed as to which facet of Mana can be seen.

Sort of like the premise in some religions that there is 1 god, but sects with that religion disagree on the interpretation of gods will/book. Your druids can see the blue "face" as their berries affect their vision, whereas the nomads only see the orange "face".
They are tapping into different aspects/frequencies of the same entity, if a piece of paper is green but you can only perceive frequencies in the yellow band, it looks yellow. but if you can only perceive frequencies in the blue band, it looks blue.

Take this analogy a little further and you can quite happily have a sectarian conflict. Different perspectives on the same "god" figure have caused enough war and death in the real world, between factions convinced only their god is the one true god.
I'll stop there as I don't wish to upset any theists.

They are unaware of how the others see Mana and interact with it because, well, it's not their way. They know of the "blue Mana" and how to best interact with it, but have not experimented with others because (as suggested in other answers) the relevant substances were not available in their area/there is an overabundance of blue-Mana-interacting stuff compare to orange-Mana-interacting stuff, and the result is that any visible "Orange" is simply too faint to see.
Maybe, the druid bloodlines just results in no/too few females with the extra "orange cone", so even if these substances were available, they wouldn't work, or the chances of a compatible woman eating the right fruit/flesh are too slim.
More drastic, there are markers in the respective genomes that literally make your blue berries lethal to consume for the nomads or vice versa (though, this might cause issues if you want your conflict to be resolvable...) and so they learned early on to avoid them.

So, they encounter the nomads and see them "working magic", but the patterns of "blue Mana" they would expect to see around someone who is, say, summoning up a plate to eat off of, are not there/different. Each group perceive a disturbance, like a ripple in a pond, caused by the magic of the other, but can't see the thing that started the ripple moving. The pond/true Mana is affected in the same way from a blue object/Mana or an orange object/Mana, and the orange/Blue Manas both exibit this change (a ripple) So the effects are mutually visible, if not the root cause.

Your Dragons, then, have the true sight. They perceive Mana as it really is, without needing the consumption of substances to permit so. All creatures have varying degrees of perception of/interaction with each blue/orange Mana, as their smaller minds cannot comprehend the true complexity of Mana.